Damper-rod scrubber

ABSTRACT

A wet scrubber having spray means for spraying a liquid into a passageway, and a rod scrubber positioned downstream of the spray means by which impurities can be removed from the gas stream. The rods of the scrubber are rotatably mounted, so that they can be rotated to a position parallel to the gas flow when it is desired. The rods are removably attached, so that they can be readily replaced if the need arises.

Waited States Eatent 91 Jonakin [4 May I1, 973

[54] DAMPER-ROD SCRUBBER [75] Inventor: James Jonakin, Simsbury, Conn.

[73] Assignee: Combustion Engineering Inc., Windsor, Conn.

[22] Filed: July 21,1971

[21] Appl. No.: 164,762

[52] US. Cl. ..261/109, 55/226, 55/230, 55/241, 261/111 [51] Int. Cl...B01f 3/04 [58] Field of Search ..55/233, 257, 226, 55/230, 240, 241;261/1 1 1, 112, 108, 109, 83

[56] References Cited UNITED STATES PATENTS 3,348,825 10/1967 Mcllvaine..55/257 X 3,488,039 l/197O Ekman ..55/241 X 3,522,000 7/1970 Kinney..261/1 ll X 3,544,087 12/1970 Mcllvaine 55/233 X 3,680,282 8/1972 Kent..55/233 Primary ExaminerTim R. Miles Assistant Examiner-Richard L.Chiesa Attorney-Carlton F. Bryant et al.

[ ABSTRACT A wet scrubber having spray means for spraying a liquid intoa passageway, and a rod scrubber positioned downstream of the spraymeans by which impurities can be removed from the gas stream. The rodsof the scrubber are rotatably mounted, so that they can be rotated to aposition parallel to the gas flow when it is desired. The rods areremovab1y attached, so that they can be readily replaced if the needarises.

4 Claims, 3 Drawing Figures 34 tunl auuguuuunm PATENTEBIAY H9153,730,499

SHEET 1 BF 2 INVENTOR. J14 ME 5 IONA KIN PAIENTEB 1 SHEET 2' [IF 2 FIG 3rllllnlllllull INVENTOR. JAME9 IONA KIN WJ 0 0/ 4rra2A/EY DAMPER-RODSCRUBBER BACKGROUND OF THE INVENTION The invention relates to a wetscrubber for removing impurities from dirty gases. Many industries,especially where combustion processes are carried out, have beencompelled in recent times to install means for removing impurities fromgases that are being exhausted to the atmosphere. One such means used isa rod scrubber consisting of a plurality of bars or rods which extendtransversely across the width of a gas passage. A spray is locatedupstream of the rods, and the water as it passes through the openingsbetween the rods collects the gaseous impurities.

In some combustion installations, for example furnaces of steamgenerating units, the provision for buming alternative fuels is made.Thus, for example, a dirty fuel such as coal which contains ash andsulfur may be burned during certain times, and a clean fuel such asnatural gas is used at other times. When coal is burned, the exhaustgases have to be cleaned. The exhaust from the combustion of natural gasdoes not have to be cleaned. Thus it is desirable to remove the rodscrubber from the exhaust gas passageway when burning natural gas, sothat fan power requirements can be reduced. Also as the steam generatingload varies, the volume of exhaust varies, and thus the pressure dropacross the scrubber varies. Since the cleaning efficiency of thescrubber is dependent on the differential pressure across thescrubber,it is desirable to be able to add or remove scrubber rods as the load onthe steam generator moves up or down.

SUMMARY OF THE INVENTION The wet scrubber of my invention utilizes aplurality of scrubber rod beds, any one or all of which can be rotated90 to a position where the rods are parallel to the flow of gases,thereby effectively removing them from the gas stream. In addition, therods are removably secured so that the width of the slits between therods can be varied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side view of awet scrubber constructed in accordance with the invention;

FIG. 2 is a sectional view taken on lines 22 of FIG. 1; and I FIG. 3 isa view similar to FIG. 2, after the scrubber rods have been rotated 90.

DESCRIPTION OF THE PREFERRED EMBODIMENT Looking now to FIG. 1 of thedrawings, designates a wet scrubber constructed in accordance with theinvention. Dirty gases to be cleaned flow through duct 12 from a source,for example the furnace of a steam generator. These dirty gases arefirst subjected to a water spray from sprinkler 16, located in the upperportion of vertical duct 14. The gases together with the water then passthrough a rod scrubber 18, where a large percentage of the impuritiesare removed with the water.

The gases then flow through a second water spray from sprinkler 20, andthrough a second bed of scrubber rods 22, where the gases are againwashed.

The separated water droplets capture the solid particles and absorbcertain gases, and fall by gravity to the floor of the scrubber housing,and are removed by pump 24. The gases leaving rod scrubber 22 reversetheir direction and flow upwardly through passage 26 to the outlet 30,where they are discharged to the atmosphere. Positioned within passage26 is a demister 28, which can be in the form of a plurality of zig-zagbaffle plates. The continuous changing of direction of the gases flowingthrough the demister 28 causes separation of most of the fine waterdroplets still remaining in the gas stream. This water runs down thesurfaces of the baffle plates, and drops to the scrubber housing floor,to be removed by pump 24.

As seen in FIGS. 2 and 3, the rods 22 are mounted on a rotatable axle35. By means of motor 34, the rods 22 can be rotated 90 (FIG. 3), so matthe rods are parallel to the walls of duct 14. This effectively removesthe rods from the gas passage as far as cleaning is concerned, and alsowith respect to their forming a restriction in the flow path. Motor 32(FIG. 1) is used to rotate the rods of scrubber 18 to a vertical orhorizontal position. Thus the rods of both rod scrubbers l8 and 22 canbe rotated so that they are parallel to the walls of the gas passage.This would be done when a clean fuel, for example natural gas, was beingburned in the furnace.

Alternatively, either one or both of the rod scrubber beds could beplaced in their operating positions so that the rods extend transverselyof the gas passage. As mentioned previously, the cleaning efficiency isdependent on the pressure drop across the scrubber rod beds, whichpressure drop is determined by the volume of gases passing therethrough.For example, when a steam generator is operating at full load, there maybe 1 million cubic feet per minute of gases passing through the wetscrubber 10. With just rod scrubber 18 in operation, the pressuredifferential across the rod scrubber may be 8 inch water gauge. When thesteam generator is operating at half load, there may only be 500,000 ft./min. of gases, and the pressure differential across rod scrubber 18 mayonly be 2 or 3 inch water gauge. By placing the rod scrubber 22 inoperation, the pressure differential across both rod scrubbers 18 and 22may again approximate 8 inch water gauge. If, the greatest cleaningefficiency for the amount of impurities in the gases were determined tobe 8 inch pressure differential, then both rod scrubbers would be placedin operation when the unit was operating at half load.

Another feature of the invention is the simplicity with which the sizeof the scrubber rods can be changed, thereby changing the width of theslits between the rods. As seen in FIGS. 2 and 3, the rods are made upof inner rod members 36, which are integral with the axle 35. Slippedover the inner rod members 36 are outer sleeve members 38. Sleevememscrubber bed arrangements, depending on whether both beds are inoperating position, or just bed 18 or bed 22 alone. The rods or rodscrubber 18 are made up of inner rods and outer removable sleeves, as isthe case of rod scrubber 22.

What is claimed is:

1. In a wet scrubber for removing impurities from gases, passage meansthrough which the gases flow, spray means for spraying a liquid into thepassage means, a plurality of parallel, spaced, rod means extendingtransversely across the passage means downstream of the spray means, andmeans for rotating the rod means 90, so that the rod means are parallelto the axis of the passage means.

2. The wet scrubber set forth in claim 1, wherein each of rod means ismade up of an inner rod, and an outer sleeve surrounding inner rod, andmeans for removably securing the outer sleeve to the inner rod, so thatthe outer sleeve can be replaced when desired.

3. In a wet scrubber for removing impurities from gases, passage meansthrough which the gases flow,

passage means downstream of the first rod means, thereby forming aplurality of slits between the second rod means through which the gasesmay flow, and means for rotating the second rod means so that the secondrod means are parallel to the axis of the passage means.

4. The wet scrubber set forth in claim 3, wherein the first rod meansare of a different size than the second rod means, so that the slitsbetween the first rod means have a different width than that of theslits between the second rod means.

1. In a wet scrubber for removing impurities from gases, passage meansthrough which the gases flow, spray means for spraying a liquid into thepassage means, a plurality of parallel, spaced, rod means extendingtransversely across the passage means doWnstream of the spray means, andmeans for rotating the rod means 90*, so that the rod means are parallelto the axis of the passage means.
 2. The wet scrubber set forth in claim1, wherein each of rod means is made up of an inner rod, and an outersleeve surrounding inner rod, and means for removably securing the outersleeve to the inner rod, so that the outer sleeve can be replaced whendesired.
 3. In a wet scrubber for removing impurities from gases,passage means through which the gases flow, spray means for spraying aliquid into the passage means, a plurality of first parallel, spaced,rod means extending transversely across the passage means downstream ofthe spray means, thereby forming a plurality of slits between the firstrod means through which the gases may flow, means for rotating the firstrod means 90*, so that the first rod means are parallel to the axis ofthe passage means, a plurality of second parallel, spaced, rod meansextending transversely across the passage means downstream of the firstrod means, thereby forming a plurality of slits between the second rodmeans through which the gases may flow, and means for rotating thesecond rod means 90*, so that the second rod means are parallel to theaxis of the passage means.
 4. The wet scrubber set forth in claim 3,wherein the first rod means are of a different size than the second rodmeans, so that the slits between the first rod means have a differentwidth than that of the slits between the second rod means.